In old western movies, people predictably squared up against each other at “high noon” for a “fair gunfight,” and it was always the good guy who was the faster draw. Events like that didn’t happen in real life even in the Old West, and they don’t happen now. Police officers are at a disadvantage in encounters with citizens.

Officers must confront the behavior of aggressors they don’t know, and an aggressor’s intent must be inferred from what he’s already done. The aggressor has the advantage of knowing the outcome he intends and the ability to set the pace at which the encounter unfolds. An officer usually has the advantage of superior training and resources, but other factors in those encounters contribute to a challenging dynamic. Those factors include concern for the protection of innocent people, an inability to control the pace of the encounter, stress associated with balancing potentially lethal choices, and changes in the ability to perceive under stress.

To make the situation more challenging, officers in armed encounters are forced to react to the actions of an aggressor. The aggressor always has a time advantage, since it takes longer for an officer to react than it does for the aggressor to act. Therefore, to protect themselves and the people around them, officers must anticipate potential threats and must be prepared to neutralize those threats before the aggressor acts. A responding officer must continuously assess the threat. If a threat is identified, the officer must decide how to reduce it in a way that doesn’t put others at unnecessary risk. That process takes time, during which the aggressor may be moving toward his objective. Officers may have only fractions of a second to decide how to stop an aggressor.

As a society we feel sympathy for those who are mentally impaired or in crisis. We may even wish to intervene to assist them, or to give them the benefit of the doubt when they behave erratically. Conditions like that don’t render an aggressor harmless. In fact, influences that make people less predictable often make them more dangerous.

Intoxication or mental impairment may make a person very strong or reluctant to communicate or to follow instructions. Intoxicated aggressors are often insulated from pain, so that non-lethal weapons are ineffective in stopping them. The law enforcement response must always be based on the actions of the aggressor and the context in which they occur.

When police respond to a threat, they must ensure public safety, their own safety, and, if possible, the aggressor’s safety. Crisis intervention will often be attempted and many officers have been trained to slow crisis situations down, when possible. Those techniques have limits, and the pace of an encounter and its outcome are ultimately within the control of the aggressor.

In movies, it appears easy to take a knife away from an assailant. In reality, disarming such a person is a dangerous tactic that creates an unjustifiable risk of injury to the officer and others. An officer’s appropriate response to deadly force is to use force that can immediately stop the aggressor’s ability to injure others. An edged weapon can cause death or serious injury.

In addition, it takes less time for a person with a knife to assault an officer within thirty feet or more, than it takes for the officer to recognize the threat, draw his weapon, and defend himself. Pepper spray and batons are generally not a safe alternative against an edged weapon. Depending upon the situation, position, and actions of the aggressor, and the presence of other officers providing cover, a TASER might not be a safe option either. In most cases, using those would be inappropriate and place citizens and officers in jeopardy.

Hollywood has created another myth, that of the Old West law man shooting a weapon out of an aggressor’s hand or shooting the aggressor in the arm or leg, and thereby stopping or disarming him. Like all of the Hollywood myths associated with police-citizen encounters, that one doesn’t stand up to scrutiny. Officers are not trained to shoot to kill, but to shoot to stop the aggressor, so their training tells them to aim for the “center mass” – the middle of the largest exposed area on the aggressor – because aiming there increases the likelihood of hitting and stopping the aggressor.

That’s critical, because the officer is reacting to the stress of an encounter and both the officer and the aggressor may be moving. The likelihood of hitting a small, rapidly moving target, such as a foot or hand, is low. An aggressor can move his hand into a shooting position faster than an officer can react to pull the trigger. As a result, an officer can’t reliably hit a threatening suspect’s forearm or a weapon in a suspect’s hand, even if both the officer and the subject are stationary, which they rarely will be in such an encounter.

Non-lethal tools, including Extended Range Impact Munitions (bean-bags) or TASERs may be used if less-than-lethal force is appropriate. Non-lethal tools, however, often don’t incapacitate a subject. Non-lethal tools often only startle, distract, or create minor pain to the subject, or only momentarily stop him. Because it is sometimes ineffective at stopping a threat, non-lethal force requires that a second officer be prepared to use lethal force.

The fact that an assailant was shot in the back does not necessarily mean he was running away from the officer and wasn’t a threat when the officer shot. An aggressor might start out presenting a face-to-face threat, but in the times it takes for the officer to perceive the threat, decide to shoot, draw his weapon, and pull the trigger, the assailant can partially turn away, exposing his back. Furthermore, suspects frequently fire weapons behind them as they run away.

Even though a police officer will shoot such a suspect in the back, that doesn’t mean the fleeing suspect wasn’t a threat to the officer or others. Sometimes an early shot from the officer will incapacitate the assailant, but before the officer can perceive that, he might fire several additional shots. One of those shots might hit the assailant in the back as he falls through the path of bullets that the officer fires before perceiving that the threat has been neutralized.

An attacker can be shot many times and continue to attack before his wounds cause him to stop. An aggressor can sustain multiple fatal wounds to the head, torso, and other body parts, but continue to be mobile and lethal for a time. Drugs or an altered mental state can make an aggressor less responsive to the immediate effects of being shot, and officers are trained to shoot until the threat is stopped.

If they see no reaction, and the threat persists, officers will continue to shoot. With as many as four rounds fired per second, an aggressor may be struck multiple times before he stops attacking. If more than one officer uses lethal force, even more rounds may be fired before the threat is stopped.

Although videos of police use of force are helpful, they can’t tell the whole story. They are a two-dimensional record of a three-dimensional event. They only record from one perspective, and it’s often not that of the officer. Think of a football game, for example, where officials often play back video from many angles to make a final call. Those calls often remain controversial, even though the officials have the benefit of multiple viewing angles, consultation, and time to guide their decisions. Officers in a lethal encounter have none of those benefits.

Also, cameras often only record a portion of the event and are limited by technological specifications. Some cameras are triggered to record by motion. Others can distort the action by recording at rates as slow as ten frames per second. So, even when they are present, cameras can never tell the whole story from the officer’s perspective.

Video can help determine whether an officer was justified in the use of deadly force. An officer’s use of force must be judged from the perspective of the officer at the moment deadly force was used, taking into consideration information the officer had at the time. To do that properly, all facts known to the officer at the time must be considered, not just what is displayed on a video.